The invention relates generally to adhesives, such as flooring adhesives, and more particularly, to adhesives that have low emissions of undesirable materials, such as volatile organic compounds (VOCs).
Many products are assembled using adhesives. For example, various flooring products made from wood, vinyl, tile, carpet and so forth are permanently adhered to a surface or substrate through the use of an adhesive. Commonly used adhesives include those sold under the trademarks Taylor Enviotec 2090 Vinyl Adhesive and Taylor Envirotec 2055 Premium Carpet Adhesive sold, by W.F. Taylor Co. of Fontana, Calif.
There are at least two general types of adhesives: two component adhesives and one component adhesives. Two components reactive adhesives are generally formed with a resin component and a hardener component and the resin and hardener are mixed immediately prior to application. This causes a chemical reaction to occur which typically initiates some type of cross-linking process. Two component adhesives are often considered undesirable because considerable mixing of the components must occur just prior to use. This can be inconvenient. Also, just the right amount of adhesive must be mixed prior to application. If too much is mixed, or the working “pot” time is exceeded, the adhesive will harden and the excess must be discarded. Reactive urethane type adhesives contain materials such as isocyanates, which are often considered undesirable.
Single component adhesives can be more convenient to use than two component adhesives. Many single component adhesives are solvent-based adhesives in which an adhesive composition is mixed with a solvent and packaged in a drum, can or tube. After the adhesive is applied to a substrate, the solvent evaporates, which causes the adhesive to cure.
The solvents used in certain conventional solvent-based adhesives are believed by some to be undesirable. For example, many solvent-based adhesives emit VOCs. Depending on the working environment, available ventilation, and the amount of adhesive to be used, some consider the VOC's and other emitted chemicals to be disadvantageous. Other single component adhesives contain excessive amounts of water, which can damage wood surfaces. There are other single component reactive adhesives such as moisture cure urethanes, but they typically exhibit emission problems because they give off solvents and other potentially dangerous materials such as isocyantes (MDI and TDI).
Accordingly, it is desirable to provide an improved adhesive which overcomes drawbacks and inadequacies of conventional adhesives.